speciation and the threespine stickleback answer key

Search time is then manipulated by varying absolute abundance of prey.

Also, we found no evidence of curvature in the intraspecific competition function. Since the phenomenon occurs repeatedly in different contact zones of marine and freshwater sticklebacks around the world, scientists now have a multitude of research sites at their disposal for more in-depth studies of the molecular basis of adaptation and speciation. We found that the evolutionary outcome depends on the inherent costs or benefits of widening the niche. Dietreversal reduced the natural morphological gap between these two species, -1% to 58%, depending on the trait.

Speciation by natural selection occurs by 2 general mechanisms (4, 7). One of the most remarkable discoveries about this gene is that the low-armor Eda allele found in almost every freshwater population around the Northern Hemisphere belongs to the same clade of low-armor alleles (Fig. In a laboratory experiment, Dettman et al. Mate selection in three-spine sticklebacks (. • Habitat choice may reduce or increase the scope for other processes to contribute to adaptation. et al. We find evidence for assortative mating in the form of a positive correlation between mated pairs' diets (measured using stable isotopes). Carp can disperse their eggs via the digestive system of ducks, and dispersal of a single Prussian carp egg could establish a new population, according to a study. Global survey of mitochondrial DNA sequences in the threespine stickleback: evidence for recent colonizations. The repetitive origin of species under the transporter process proposed herein seems possible only under ecological speciation.

If so, then sexual selection may be implicated in the speciation process. Although numerous cases now indicate the importance of ecological speciation in nature, very little is known about the genetics of the process. Generally, body is streamlined with a robust set of spines, a pelvic gridle and numerous lateral bony plates. Fenn (in press), Kristjánsson, B.K. Our “transporter”* hypothesis is founded on what we know already about Eda and Kitlg and adds what we suspect regarding the source of standing variation in the marine population. High-armor, marine populations are in red, low-armor freshwater populations are in blue. One of Darwin's greatest ideas was that new species originate by natural selection (1). We show that evolution under branching conditions selects for assortativeness and thus allows sexual populations to escape from fitness minima.

6). The Goldilocks effect of lake size on within-population diversity in stickleback, Evolutionary Implications of Habitat Choice, New criteria for sympatric speciation in the genomic era, Introduction to the evolutionary biology of the threespine stickleback, REINFORCEMENT OF STICKLEBACK MATE PREFERENCES: SYMPATRY BREEDS CONTEMPT, SEXUAL SELECTION AGAINST HYBRIDS BETWEEN SYMPATRIC STICKLEBACK SPECIES: EVIDENCE FROM A FIELD EXPERIMENT, A test of ecological selection against young-of-the-year hybrids of sympatric sticklebacks, Evolution of niche width and adaptive diversification, Evolutionary Branching and Sympatric Speciation Caused by Different Types of Ecological Interactions, Can intraspecific competition drive disruptive selection?

For these models, we investigate the ecological and evolutionary conditions that allow for evolutionary branching and establish that branching is a generic and robust phenomenon. A prerequisite for evolutionary branching is that directional selection drives the population toward a fitness minimum in phenotype space. Furthermore, reverse speciation can lead to novel phenotypes [1, 2], which may in turn produce novel ecological effects. Reinforcement and other consequences of sympatry. However, although disruptive selection and assortative mating seem to co-occur in sticklebacks, weak disruptive selection followed by weak assortative mating appears to not allow much differentiation in sympatric populations, rather these population shows adaptation to fluctuating environment instead, ... Studies have shown that ecologically-based divergent selection can overcome the homogenizing effects of gene flow resulting in reproductive isolation and possibly speciation -even in sympatry McKinnon et al. An experimental test in natural populations of sticklebacks, Optimal Foraging and the Size Selection of Prey by the Bluegill Sunfish (Lepomis Macrochirus), Clarifying mechanisms of adaptation to novel habitats, Eco-evolutionary dynamics and community stability, RInSp - analysis of individual specialization in resource use, Morphological segregation of Icelandic threespine stickleback (Gasterosteus aculeatus L).


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